Contributions of Semantic Web Tools to Relational Models

5International audienceIn the quest for models that could help to manage the data, relational model has been the most efficient data management solution and the data management bedrock of business information processing. Approaches have resorted to the integration of data analysis improvement knowledge and data interpretation using relational models. The availability of multiple heterogeneous, autonomous, distributed data sources containing related information has created a need for integrated access to these information systems. Although the relational models are recommended through their advantages, they have also some limits such as the data structure and relation and also the interoperability between databases. This paper studies the contributions of answering limits through relational model through the efforts of the Semantic Web Community (W3C)

Completeness and Ambiguity of Schema Cover

Given a schema and a set of concepts, representative of entities in the domain of discourse, schema cover defines correspondences between concepts and parts of the schema. Schema cover aims at interpreting the schema in terms of concepts and thus, vastly simplifying the task of schema integration. In this work we investigate two properties of schema cover, namely completeness and ambiguity. The former measures the part of a schema that can be covered by a set of concepts and the latter examines the amount of overlap between concepts in a cover. To study the tradeoffs between completeness and ambiguity we define a cover model to which previous frameworks are special cases. We analyze the theoretical complexity of variations of the cover problem, some aim at maximizing completeness while others aim at minimizing ambiguity. We show that variants of the schema cover problem are hard problems in general and formulate an exhaustive search solution using integer linear programming. We then provide a thorough empirical analysis, using both real-world and simulated data sets, showing empirically that the integer linear programming solution scales well for large schemata. We also show that some instantiations of the general schema cover problem are more effective than others

A framework for information integration using ontological foundations

With the increasing amount of data, ability to integrate information has always been a competitive advantage in information management. Semantic heterogeneity reconciliation is an important challenge of many information interoperability applications such as data exchange and data integration. In spite of a large amount of research in this area, the lack of theoretical foundations behind semantic heterogeneity reconciliation techniques has resulted in many ad-hoc approaches. In this thesis, I address this issue by providing ontological foundations for semantic heterogeneity reconciliation in information integration. In particular, I investigate fundamental semantic relations between properties from an ontological point of view and show how one of the basic and natural relations between properties – inferring implicit properties from existing properties – can be used to enhance information integration. These ontological foundations have been exploited in four aspects of information integration. First, I propose novel algorithms for semantic enrichment of schema mappings. Second, using correspondences between similar properties at different levels of abstraction, I propose a configurable data integration system, in which query rewriting techniques allows the tradeoff between accuracy and completeness in query answering. Third, to keep the semantics in data exchange, I propose an entity preserving data exchange approach that reflects source entities in the target independent of classification of entities. Finally, to improve the efficiency of the data exchange approach proposed in this thesis, I propose an extended model of the column-store model called sliced column store. Working prototypes of the techniques proposed in this thesis are implemented to show the feasibility of realizing these techniques. Experiments that have been performed using various datasets show the techniques proposed in this thesis outperform many existing techniques in terms of ability to handle semantic heterogeneities and performance of information exchange

Gestion de métadonnées utilisant tissage et transformation de modèles

The interaction and interoperability between different data sources is a major concern in many organizations. The different formats of data, APIs, and architectures increases the incompatibilities, in a way that interoperability and interaction between components becomes a very difficult task. Model driven engineering (MDE) is a paradigm that enables diminishing interoperability problems by considering every entity as a model. MDE platforms are composed of different kinds of models. Some of the most important kinds of models are transformation models, which are used to define fixed operations between different models. In addition to fixed transformation operations, there are other kinds of interactions and relationships between models. A complete MDE solution must be capable of handling different kinds of relationships. Until now, most research has concentrated on studying transformation languages. This means additional efforts must be undertaken to study these relationships and their implications on a MDE platform. This thesis studies different forms of relationships between models elements. We show through extensive related work that the major limitation of current solutions is the lack of genericity, extensibility and adaptability. We present a generic MDE solution for relationship management called model weaving. Model weaving proposes to capture different kinds of relationships between model elements in a weaving model. A weaving model conforms to extensions of a core weaving metamodel that supports basic relationship management. After proposing the unification of the conceptual foundations related to model weaving, we show how weaving models and transformation models are used as a generic approach for data interoperability. The weaving models are used to produce model transformations. Moreover, we present an adaptive framework for creating weaving models in a semi-automatic way. We validate our approach by developing a generic and adaptive tool called ATLAS Model Weaver (AMW), and by implementing several use cases from different application scenarios.L'interaction et l'interopérabilité entre différentes sources de données sont une préoccupation majeure dans plusieurs organisations. Ce problème devient plus important encore avec la multitude de formats de données, APIs et architectures existants. L'ingénierie dirigée par modèles (IDM) est un paradigme relativement nouveau qui permet de diminuer ces problèmes d'interopérabilité. L'IDM considère toutes les entités d'un système comme un modèle. Les plateformes IDM sont composées par des types de modèles différents. Les modèles de transformation sont des acteurs majeurs de cette approche. Ils sont utilisés pour définir des opérations entre modèles. Par contre, il y existe d'autres types d'interactions qui sont définies sur la base des liens. Une solution d'IDM complète doit supporter des différents types de liens. Les recherches en IDM se sont centrées dans l'étude des transformations de modèles. Par conséquence, il y a beaucoup de travail concernant différents types des liens, ainsi que leurs implications dans une plateforme IDM. Cette thèse étudie des formes différentes de liens entre les éléments de modèles différents. Je montre, à partir d'une étude des nombreux travaux existants, que le point le plus critique de ces solutions est le manque de généricité, extensibilité et adaptabilité. Ensuite, je présente une solution d'IDM générique pour la gestion des liens entre les éléments de modèles. La solution s'appelle le tissage de modèles. Le tissage de modèles propose l'utilisation de modèles de tissage pour capturer des types différents de liens. Un modèle de tissage est conforme à un métamodèle noyau de tissage. J'introduis un ensemble des définitions pour les modèles de tissage et concepts liés. Ensuite, je montre comment les modèles de tissage et modèles de transformations sont une solution générique pour différents problèmes d'interopérabilité des données. Les modèles de tissage sont utilisés pour générer des modèles de transformations. Ensuite, je présente un outil adaptive et générique pour la création de modèles de tissage. L'approche sera validée en implémentant un outil de tissage appel

Ferramenta de Mapeamento de Modelos para uma Plataforma de Produtos de Seguros

Atualmente um sistema informático tem normalmente que interagir/comunicar com diversos sistemas externos, que disponibilizam informação em diversos formatos e utilizando diferentes modelos. Na integração deste tipo de sistemas existe a necessidade de transformar diferentes modelos e/ou agregar informação para posterior utilização. Este processo de integração pode ser um processo complexo e demorado, dependendo da complexidade inerente do negócio associado. Este trabalho pretende apoiar e desenvolver o trabalho previamente realizado pela empresa msg life Iberia que tem vindo a desenvolver uma aplicação de comercialização de seguros denominada Sales & Service, no ramo de Vida e Não Vida, que se distingue pela capacidade de integração de diferentes PDS – Product Definition System e pela capacidade de customização dos diferentes produtos existentes nesses sistemas, tanto ao nível dos próprios produtos como à forma de apresentação dos mesmos, sem necessidade de desenvolvimento de uma aplicação de raiz para tal. Esta capacidade é alcançada com base na existência de um modelo canónico, que representa um produto de seguros, genérico o suficiente para suportar todas essas variações. Os modelos existentes nos diferentes PDS são extensos e com grande nível de especificidade o que torna o processo de integração de um novo Product Definition System num processo demorado e custoso. Pretende-se desenvolver uma ferramenta de mapeamento entre os diferentes modelos utilizados que permita facilitar e automatizar dentro do possível todo o processo de integração com diferentes PDS. Esta ferramenta deve suportar vários tipos de transformação e apresentar ganhos relevantes comparativamente ao processo manual atualmente em prática. Para atingir estes objetivos pretende-se tirar partido de técnicas de Model to Model Transformation e a utilização das melhores práticas preconizadas pela utilização do paradigma Model Driven Architecture e de outras técnicas de mapeamento entre objetos.Currently a computer system usually has to interact/communicate with several external systems, which provide information in different formats and using different models. In the integration of this type of systems there is a need to transform different models and/or to aggregate information for later use. This integration process can be a complex and timeconsuming process, depending on the inherent complexity of the associated business. This work intends to support and develop the work previously carried out by the company msg life Iberia which has been developing an insurance sales application called Sales & Service in the field of Life and Non Life, distinguished by the integration capacity of different PDS – Product Definition System and the ability to customize the different products in these systems, both in terms of the products themselves and also in the way they are presented, without the need to develop an application from the ground up for achieving that. This capability is achieved on the basis of the existence of a canonical model, which represents an insurance product, generic enough to support all these variations. The existing models in the different PDS are extensive and with a high level of specificity which makes the process of integrating a new Product Definition System into a time-consuming and costly process. It is intended to develop a mapping tool among the different models used to facilitate and automate the entire integration process with different PDS. This tool must support various types of transformation and present significant gains compared to the manual process in place nowadays. To achieve these objectives we intend to take advantage of Model to Model Transformation techniques and the use of the best practices recommended by the use of the Model Driven Architecture paradigm and other mapping techniques between objects